Recently, mobile telephone services were introduced wherein a subscriber only needs one single mobile phone that is suitable for calling via Voice Over IP (VOIP) and via a mobile telecommunications network such as Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), High Speed Packet Access (HSPA), Long Term Evolution (LTE) or the like. If the subscriber resides within a predetermined home area, e.g. at home, he may call via a radio based connection such as Wireless Local Area Network (WLAN), WIFI (or other IEEE 802.11 compatible connections), or Bluetooth. These radio based connections are collectively denoted as UMA (Unlicensed Mobile Access). GSM, UMTS, HSPA, LTE and the like are denoted as GAN (Global Access Networks). Phones capable of connection in both UMA and GAN are denoted as UMA/GAN phones. For a subscriber to use the phones capabilities he needs to have either GAN and UMA subscriptions or a combined UMA/GAN subscription. Below, it is assumed that a subscriber has a combined UMA/GAN subscription. Such a subscriber is referred to as a UMA/GAN-subscriber.
Nowadays UMA/GAN-subscribers may have the possibility to make ‘calls for free’ with a UMA/GAN mobile telecommunications device, when inside the home area, e.g. when calling via Voice Over Internet Protocol (VOIP). These VOIP calls may be charged by a monthly fee for IP (Internet Protocol) access.
When a subscriber has a UMA-Fixed subscription having both a UMA/GAN mobile telecommunications device and a fixed telecommunications device, each having a unique telephone number, it is also possible to receive calls that are set-up to the fixed (geographical) number of the fixed telecommunications device on the UMA/GAN mobile telecommunications device number in case the UMA/GAN mobile telecommunications device associated with the UMA/GAN-subscriber associated with this fixed number is within Wireless Local Area Network (WLAN) coverage (UMA Fixed). Hence it is possible to route calls made to one of a plurality of telephone numbers to a UMA/GAN mobile telecommunications device, where the UMA/GAN mobile telecommunications device can be used as a ‘one phone concept’.